1. Field of the Invention
The present invention relates to a direct current motor appropriate to an exhaust gas recycle valve device in which the direct current motor is used for a vehicle height adjusting device or an exhaust gas recycle system mounted in a vehicle.
2. Description of Related Art
Published Unexamined Japanese Patent Application No. H11-168851 (1999) discloses a known direct current motor. This type direct current motor is principally composed of a rotor, a stator functioning as a case for surrounding the rotor and a commutator. Coils are arranged in the rotor, a plurality of permanent magnets arranged at equal intervals are tightly fitted to an inner peripheral face of the rotor, and the commutator can be coaxially rotated together with the rotor. Also, noise eliminating parts such as condensers, varistors and the like are arranged to eliminate noise generated in a motor drive operation. For this reason, these components are arranged between terminals functioning as an electric power supplying unit of the direct current motor.
However, because the conventional direct current motor has the above-described structure, there is a problem that the noise generated in the motor drive operation cannot be sufficiently eliminated.
An object of the present invention is to provide, with due consideration to the drawbacks of the conventional direct current motor, a direct current motor in which a noise eliminating element is arranged to reliably eliminate noise generated in a motor drive operation.
A direct current motor of the present invention comprises a stator in which coils corresponding to N phases are arranged almost at equal intervals in a circle-circumferential direction of stator cores, a rotor in which a plurality of permanent magnets are respectively arranged at positions corresponding to the coils of the stator, and a current carrying device for commutating direct current supplied from a power source to N-phase current in cooperation with the rotor and carrying the N-phase current to each coil of the stator. The direct current motor further comprises a noise eliminating member arranged in an internal space of the current carrying device to be connected with the coils of two coil phases. Accordingly, noise generated in a motor operation time can be reliably eliminated by the noise eliminating members.
In the direct current motor of the present invention, the noise eliminating members are fixed to the current carrying device by adhesive material or by caulking. Therefore, the noise eliminating members can be easily fitted to the current carrying device.
In the direct current motor of the present invention, the current carrying device comprises a plurality of plates, each of which corresponds to one coil phase of the stator, and one noise eliminating member is connected with each pair of plates adjacent to each other. Therefore, noise generated in a motor operation time can be reliably eliminated by the noise eliminating members, and a space between each pair of plates can be effectively used. Therefore, a small-sized direct current motor can be manufactured.